This invention relates to lower units for marine propulsion devices, such as outboard motors and stern drive units, and, more particularly, to such lower units including anodes for cathodic protection.
When marine propulsion devices are operated in sea water, a galvanic action between parts of dissimilar metals exposed to electrolytic sea water can cause severe corrosion of the less noble metal, particularly aluminum. Anodes have been used to reduce the corrosive effect caused by this galvanic action.
Examples of prior art patents disclosing the use of anodes on marine propulsion devices for this purpose include the following U.S. patents:
______________________________________ Patentee U.S. Pat. No. Issue Date ______________________________________ Gruber 3,169,504 February 16, 1965 Byrd 3,240,180 March 15, 1966 Warner 3,330,751 July 11, 1967 Nakano 4,146,448 March 27, 1979 Harm et al 4,196,064 April 1, 1980 Ciampolillo 4,391,567 July 5, 1983 ______________________________________
Attention is also directed to the pending U.S. Cavil Application Ser. No. 365,295 filed Apr. 5, 1982 and the pending U.S. Cavil et al Application Ser. No. 531,462, filed Sept. 12, 1983.